The present invention is related to Japanese patent application No. Hei. 11-247698, filed Sep. 1, 1999; the contents of which are incorporated herein by reference.
The present invention relates to a measuring instrument, and more particularly, the present invention relates to a measuring instrument with an indicator.
Conventionally, for example, measuring instrument indicators are used, such as for an automobile, such as the one illustrated in JP-A-9-21655. Here, a light-emitting indicator is supported at its rotating base by a forward end of an indicator shaft that passes through a through-hole of a graduated board and a light-guiding plate. These items are concurrently disposed on a reverse surface of this graduated board and extend from a rotating machine. Also, a plurality of light-emitting elements, constituting a light source, are disposed around the indicator shaft at positions corresponding to the rotating base of the light-emitting indicator on a reverse surface side of the light-guiding plate. These light-emitting elements provide light into the light-emitting indicator through the respective through-hole of the light-guiding plate and graduated board, from the rotating base portion thereof. At the same time, light enters the light-guiding plate from the through-hole from this same source.
However, in the above-described device, light from each respective light-emitting element is incident upon both the light-emitting indicator and the light-guiding plate. As such, even though light incident upon the light-emitting indicator is sufficient, light incident upon the graduated board from the light-guiding plate through the reverse surface is insufficient. As a result, the graduated board has reduced brightness. The present invention was developed in light of these drawbacks.
The present invention overcomes these and other drawbacks by providing a measuring instrument with an indicator having light-transmitting graduated boards, a light-guiding plate provided along a reverse surface of the graduated board, a rotating inside machine provided on a reverse-surface side of the light-guiding plate and having an indicator shaft passing through a through-hole of the light-guiding plate and a through-hole of the graduated board. The measuring instrument further has light-emitting indicators supported at a forward end portion of the indicator shaft by a rotating base portion so as to rotate along a surface of the graduated board. A first light source is disposed on a reverse-surface side of the light-guiding plate around the indicator shaft which causes the light to enter the light-emitting indicator from the rotating base portion through the respective through-hole portions and causes the light to enter the graduated board through the light-guiding plate.
a second light source is disposed at a position spaced from the indicator shaft from the first light source in the radial direction and arranged to cause the light to enter the graduated board through the light-guiding plate.
As a result, the first light source illuminates the light-emitting indicator and the graduated board. The second light source illuminates only the graduated board 20a. Accordingly, even when light from the first light source on the graduated board is insufficient compared to light from the first light source on the light-emitting indicator, the second light source compensates for this insufficiency. As a result, the graduated board as well as the light-emitting indicator are properly illuminated.
In another aspect of the present invention, a black face is provided on the graduated board via an annular end plate to oppose the surface of the graduated board and light-emitting element.
In another aspect of the invention, a first light source is a plurality of light-emitting elements disposed around the indicator shaft at substantially equal distances from the indicator shaft in the radial direction. A second light source is provided which is a single light-emitting element.
In a further aspect of the invention, the measuring instrument has a wiring board provided along a reverse surface of the light-guiding plate. The first light source is a plurality of light-emitting elements provided on the wiring board and electrically connected to this wiring board and the second light source is. a single light-emitting element provided on said wiring board and electrically connected to this wiring board, and the rotating inside machine is electrically connected to the wiring board.
In another aspect of the invention, the light-guiding plate is equipped, on an opposite surface, with a concavity portion opposing the light-emitting element constituting the second light source. The second light source causes the light to enter the concavity portion before the light enters the graduated board through the light-guiding plate.
In another aspect of the invention, the first light source is a plurality of light-emitting diodes radially disposed around the indicator shaft at substantially equal distances from the indicator shaft. The second light source is a light-emitting diode.
In another aspect of the invention, a wiring board is provided along a reverse surface of the light-guiding plate, and the respective light-emitting elements are light-emitting diodes provided on the wiring board and electrically connected to the wiring board along with the rotating inside machine.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.